What are the groups of alpha thalassemia?

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Last updated: March 11, 2025 • View editorial policy

From the Research

Alpha thalassemia is classified into four main groups based on the number of alpha globin genes affected, including silent carrier, alpha thalassemia minor, Hemoglobin H disease, and Hemoglobin Bart's hydrops fetalis, as supported by the most recent study 1. The classification of alpha thalassemia is crucial for understanding the clinical manifestations and management of the disease.

  • Silent carriers have one mutated alpha globin gene and typically show no symptoms or hematologic abnormalities.
  • Alpha thalassemia minor involves two mutated genes and may cause mild anemia with microcytosis.
  • Hemoglobin H disease occurs when three alpha globin genes are affected, resulting in moderate to severe anemia, hepatosplenomegaly, and potential complications like gallstones and iron overload.
  • Hemoglobin Bart's hydrops fetalis, the most severe form, involves all four alpha globin genes and is typically fatal before or shortly after birth due to severe anemia and hydrops fetalis. This classification is important for genetic counseling and management decisions, as the severity increases with the number of affected genes, as noted in 1. The inheritance pattern is complex because humans have four alpha globin genes (two on each chromosome 16), and mutations can affect any combination of these genes, making genetic counseling essential for families at risk, as discussed in 2 and 3. While other studies, such as 4 and 5, provide additional information on thalassemia, the most recent and highest-quality study 1 provides the most relevant and up-to-date information on the classification of alpha thalassemia.

References

Research

The Clinical Phenotypes of Alpha Thalassemia.

Hematology/oncology clinics of North America, 2023

Research

Alpha- and Beta-thalassemia: Rapid Evidence Review.

American family physician, 2022

Research

Alpha-thalassaemia.

Orphanet journal of rare diseases, 2010

Research

Alpha and beta thalassemia.

American family physician, 2009

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